Question

17. If x is a real number such that x3 = 729,

then x2 + x = ?
A. 738
B. 732
C. 90
D. 84
E. 12

Answer 1

C. 90

Explanation:

If x^3 = 729, x = 9.

Then, plug that into x^2 + x

9 ^ 2 + 9 = 81 + 9 = 90